This course is completely asynchronous.

Which type of skeletal muscle fibers are typically recruited only when bursts of speed or extra strength are needed?

In living muscle, when myoglobin is oxidized (Fe2+ converts to Fe3+) a state called metmyoglobin, an enzyme reduces the cation back to Fe3+. Because the animal is alive, the levels of metmyoglobin are low at any given time. When a piece of beef sits in the refrigerator, the oxidation occurs but since the muscle is dead, the enzymatic reduction does not occur. After a few days, the levels of metmyoglobin increase. The color of the meat changes from red to:

Skeletal muscles are a mosaic of the type I, type IIA, and type IIB fibers.

What regions indicated are recruited for swimming at cruising speed?  

When oxygen levels decline within the mitochondrion, oxygen stored in the _________ of the striated muscle cell will be released and diffuse into the mitochondrion. 

What type of skeletal muscle fibers are in region A (indicated by the arrows)?

Since skeletal muscle cells are long and thin, anatomists often refer to them as _____. These cells are easily seen in pulled pork or shredded chicken as depicted below.

Which skeletal muscle fiber is the most active and always the first to be recruited to carry out a movement?

How long does it typically take for a fresh cut steak to change color when exposed to air as indicated?